1. Field of the Invention
The invention relates to a disc brake comprising a brake disc; a brake caliper on which is supported a brake applicator shaft that is actuated by means of a rotary lever and that extends transversely to an axis of rotation of the brake disc; a thrust spindle that belongs to an adjusting device and by means of which upon brake application an application force is transmitted from the brake applicator shaft onto the brake disc; and a monitoring device, in particular, for monitoring wear of the brake, a stroke of the brake, and/or readjustment of the brake.
2. Description of the Related Art
Such a disc brake is disclosed, for example, in European patent application 0 784 162 A2. According to this patent application, a wear sensor 50 and a thrust member 9 form a unitary module, wherein relative movements of the thrust spindles 10, 11 relative to a thrust member are detected by the sensor in that the sensor is connected by means of a gear wheel, toothed rod or the like to the thrust spindles. This solution requires a large number of components. Moreover, mechanical machining of bearing and contact surfaces is required. Finally, the described wear monitoring device assembled of the afore described elements needs radial mounting space within the brake.
German patent application 43 12 377 A1 shows in FIG. 3 a sensor 12 that is mounted laterally to an actuating device 6 within the brake caliper and is connected to the outer wall surface of the actuation device by means of a sliding pin 17. This solution also requires mechanical machining of the bearing and contact surfaces and, again, radial mounting space is required.
German patent application 100 36 109 A1 discloses a reference device 7 that is connected to several brake parts for carrying out measurements at several locations. Accordingly, attachments are required. Moreover, external influences can have an effect on the measured results and also on the reference device.
The above described solutions for monitoring are suitable in principle to fulfill the posed requirements. However, in particular with regard to their configuration and with regard to their arrangement within the brake, improvements are desirable which, on the one hand, require less mounting space by providing fewer parts—and thus contribute to a reduction of the size of the entire brake—and, on the other hand, are connected to the brake parts where measurements are to be taken such that a most precise sensing action is ensured. In this connection, tolerances should have no disadvantageous effect on the measured result. When changing the brake pads, it should not be necessary to readjust/calibrate the brake. The sensing or contacting action should be provided directly on the part whose position is to be determined, for example, with regard to wear or stroke of the brake.